Reliance Industries today posted a 13.7 per cent jump in its first quarter net profit to almost USD 1 billion, the highest quarterly profit by a private firm, on the back of higher refining margins, better petrochem earnings and surge in US shale gas business.

The net profit in April-June rose to Rs 5,957 crore, or Rs 20.3 per share, up 13.7 per cent from Rs 5,237 crore, or Rs 17.8 a share, in the same period a year ago, the company said in a statement.

Reliance Industries (RIL) is the first company in the private sector in India to post USD 1 billion net profit in a quarter.

Turnover surged 7.2 per cent to Rs 107,905 crore.

"RIL has delivered a record level of consolidated net profit, this quarter," said Mukesh Ambani, Chairman and Managing Director, RIL. "This was achieved despite weak regional refining margins and a planned turnaround in our refinery."

The Mumbai-based operator of the world's biggest oil refinery complex earned USD 8.7 on turning every barrel of crude oil into fuel in Q1 as compared to USD 8.4 gross refining margin (GRM) in the same period a year ago.

The GRM was, however, lower than USD 9.3 per barrel in the previous January-March quarter While revenue from refinery business rose 7.2 per cent, earnings from petrochemical business soared 9.3 per cent.

But the surprise came from oil and gas production business that posted 27.3 per cent rise in revenue and more than doubled pre-tax segment profit. This was largely due to the firm's US shale gas business, which gave a revenue of Rs 1,617 crore, higher than RIL's domestic oil gas earning of Rs 1,557 crore.

"The petrochemicals business performance highlights the strength of our portfolio-mix and end-market diversity," Ambani said. "We have a great pipeline of new projects which will give Reliance an enduring competitive advantage."

RIL, he said, was further expanding its retail business in existing markets while exploring newer markets and channels.